68 PRACTICAL ORGANIC CHEMISTRY
caustic potash on the water-bath, and then distilling. It is
freed from water by standing for twenty-four hours in a flask
one-third filled with freshly-burnt quicklime, and re-distilling
from the water-bath, using a thermometer.
Properties. — Colourless liquid ; b. p. 66—67°'; sp. gr. 0796
Methyl Iodide (lodomethane), CH3I
Dumas and Peligot, Annalen, 1835, 15, 20.
1 8 grins, methyl alcohol.
5 „ red phosphorus
50 „ iodine
Attach a flask (250 c.c.) to an upright condenser, and bring
into it the methyl alcohol and red phosphorus. Add the iodine
gradually by detaching the flask for a moment from the con-
denser. A considerable evolution of heat occurs. When the
iodine has'been added the flask is left attached to the condenser
over night, and the contents then distilled from the water-bath
using a similar apparatus to that of Fig\ 43, p. 53. The dis-
tillate is shaken up with dilute caustic soda in a separating
funnel, to remove iodine and hydriodic acid. If sufficient
caustic soda has been used the lower layer of methyl iodide will
be colourless. Separate -the methyl iodide, add a few. pieces of
solid calcium chloride, and after standing until clear, distil from .
the water-bath with thermometer. Yield 45 grams. Ethyl
iodide and the other alkyl iodides are prepared in precisely the
Properties. — Colourless, highly refractive liquid ; b. p. 45° ;
sp:gr. 2-27 at 15°.
Reaction. — Shake a few drops of methyl iodide with an
alcoholic solution of silver nitrate. A white precipitate of a
compound of silver iodide and silver nitrate is deposited, which is
decomposed and gives yellow silver iodide on adding water.
See Appendix^ p. 240.